DE112017001205T5 - A method of manufacturing a positive electrode for an energy storage device and a method of manufacturing an energy storage device - Google Patents

Abstract

A method of manufacturing a positive electrode for an energy storage device comprises the steps of: providing a current collector comprising a first region and a second region on a surface of the current collector, the first region having a carbon layer formed on the surface; wherein the surface of the second region is exposed; and selectively forming a conductive polymer layer on a surface of the carbon layer by immersing the current collector in an electrolytic solution containing a raw material monomer, and then performing an electrolytic polymerization of the raw material monomer.

Description

TECHNICAL AREA

The present invention relates to a method for producing a positive electrode for an energy storage device containing a conductive polymer, and a method for manufacturing an energy storage device.

BACKGROUND OF THE INVENTION

In particular, in recent years, attention has been paid to an energy storage device interposed between a lithium ion secondary battery and an electric double layer capacitor and taking into consideration, for example, the use of a conductive polymer as a material for a positive electrode (see PTLS 1 and 2). As the conductive polymer, for example, polyaniline and polypyrrole are known. Since a positive electrode having a conductive polymer enables a Faraday reaction to be promoted in conjunction with adsorption (dosing) and desorption (undoping) of an anion, the positive electrode has a lower reaction resistance and a higher output than the output of a positive electrode general lithium ion secondary battery.

PTL 2 proposes the use of a positive electrode comprising a plate-shaped positive current collector, a carbon layer formed on an entire surface of the positive current collector, and a conductive polymer layer formed on a surface of the carbon layer opposite to a surface of the carbon layer in contact with the pantograph, on.

In the meantime, for example, for attaching a conductive member to the positive current collector, a method of scraping, for example, a brush, the carbon layer, and the conductive polymer layer from the positive electrode is performed to expose a part of the surface of the positive current collector.

CITATION

Patent literatures

• PTL 1: Japanese Unexamined Patent Publication No. 2012-226961
• PTL 2: Japanese Unexamined Patent Publication No. 2013-232388

SUMMARY OF THE INVENTION

However, it is very likely that the method of exposing a portion of the surface of the positive current collector results in damage to an exposed surface of the positive current collector or damage to the carbon layer and the conductive polymer layer.

The present invention provides a method for producing a positive electrode for an energy storage device capable of easily exposing a part of a surface of a positive current collector without a step of scraping a part of a conductive polymer layer and a carbon layer from a positive one Perform electrode.

In view of the above circumstances, one aspect of the present invention relates to a method of manufacturing a positive electrode for an energy storage device, the method comprising the steps of: providing a current collector having a first region and a second region on a surface of the current collector, the first one Area has formed on the surface of a carbon layer, wherein the surface of the second area is exposed; and selectively forming a conductive polymer layer on a surface of the carbon layer by immersing the current collector in an electrolytic solution containing a raw material monomer, and then performing electrolytic polymerization of the raw material monomer.

Another aspect of the present invention relates to a method of manufacturing an energy storage device, the method comprising the steps of: preparing a positive electrode by the above method of producing a positive electrode for an energy storage device; and stacking or winding the positive electrode, a negative electrode, and a separator, wherein the separator is disposed between the positive electrode and the negative electrode.

The method of manufacturing a positive electrode for an energy storage device according to the present invention enables a part of a surface of a positive current collector to be easily exposed without performing a step of scraping a part of a conductive polymer layer and a carbon layer from a positive electrode , Accordingly, the positive electrode is less likely to be damaged, so that it is easy to fix a positive electrode conduction member.

list of figures

• 1 shows a perspective view of a first intermediate body 30 obtained by a step (1a) of a method of manufacturing a positive electrode for an energy storage device according to the first exemplary embodiment of the present invention.
• 2 shows a perspective view of a second intermediate body 40 obtained by a step (2a) of the method of manufacturing a positive electrode for an energy storage device according to the first exemplary embodiment of the present invention.
• 3 FIG. 12 is a plan view of a positive electrode obtained by a step (FIG. 3a) of the method of manufacturing a positive electrode for an energy storage device according to the first exemplary embodiment of the present invention, to which a lead member is attached.
• 4 shows a plan view of a first intermediate body 50 which is obtained by a method of manufacturing a positive electrode for an energy storage device according to a second exemplary embodiment of the present invention.
• 5 shows a plan view of a first intermediate body 60 which is obtained by a method of manufacturing a positive electrode for an energy storage device according to a modification of the second exemplary embodiment of the present invention.
• 6 FIG. 12 is a schematic sectional view of an example of an energy storage device obtained by a method of manufacturing an energy storage device according to the present invention. FIG.
• 7 FIG. 12 is a schematic view showing a configuration of the energy storage device shown in FIG 6 is shown.

DESCRIPTION OF THE EMBODIMENTS

[Method for Producing a Positive Electrode for an Energy Storage Device]

A method for producing a positive electrode for an energy storage device according to the present invention comprises a step (step (1)) of providing, as a first intermediate body, a positive current collector having a carbon layer formed on a part of a surface of the positive current collector is. Herein, in the first intermediate body, a first region on the surface of the positive current collector represents a region on which the carbon layer is formed, and a second region on the surface of the positive current collector represents a region on which no carbon layer is formed and in which the surface of the positive current collector is exposed. Further, the present method comprises a step (step (2)) of forming a positive electrode (the second intermediate body) by immersing the first intermediate body in an electrolytic solution containing a raw material monomer, and then conducting electrolyte polymerization of the raw material monomer to selectively form a conductive polymer layer on a surface (a surface opposite to a surface in contact with the positive current collector) of the carbon layer.

In step (2), in the second region in which the positive current collector is exposed, hardly a conductive polymer is formed, wherein on the surface (the surface opposite the surface in contact with the positive current collector) of the carbon layer, in a simple way a conductive Polymer formed on the first region of the positive current collector is formed. Accordingly, the positive electrode in which the conductive polymer layer is selectively formed on the first region can be manufactured.

No conductive polymer layer is formed on the second region of the positive current collector on which no carbon layer is formed, so that it is possible to easily fix a conductive member to the second region without a step of scraping the carbon layer and the conductive polymer layer perform. Thus, damage to the positive electrode generated by the scraping step can be prevented. This leads to an increase in the reliability of the positive electrode.

It is not clear why the conductive polymer hardly forms on the second region of the positive current collector and the conductive polymer layer is selectively formed on the surface of the carbon layer in step (2). One possibility is that a difficulty in the course of a polymerization reaction in the second region is due to the presence of an oxide film on the second region of the positive current collector, but the influence of the oxide film is not high enough to increase the contact resistance between the conduction element and one later affected pantograph.

For example, a plate-shaped current collector is used as the positive current collector. Examples of the plate-shaped current collector include a metal foil, a porous one Metal body, a stamped metal and an expanded metal. As a material for the positive current collector, for example, aluminum, an aluminum alloy, nickel and titanium may be used, preferably using aluminum and an aluminum alloy. The plate-shaped current collector has, for example, a thickness in a range of 10 microns to 100 microns inclusive.

The first region and the second region may be present on both the front surface and the rear surface of the plate-shaped current collector or on the front surface or the rear surface of the plate-shaped current collector.

The step (1) includes, for example, applying a mask to a second region to become the second region on the surface of the positive current collector, then applying a carbon paste to the entire surface of the positive current collector to form a coating film then drying the coating film to form the carbon layer. As a method of forming the mask, a publicly known technique can be used. Alternatively, a carbon paste may not be uniformly applied to the surface of the positive current collector to form a coating layer. In this case, the second area is an area to which the carbon paste is not applied. The carbon paste is produced, for example, by dispersing carbon black and a resin component in water or an organic solution. The carbon layer has a thickness in a range of, for example, 1 μm to 20 μm inclusive.

As the raw material monomer used in the step (2), any polymerizable compound capable of producing a conductive polymer, which will be described later, by oxidation in the electropolymerization can be used. The raw material monomer may comprise an oligomer. As the raw material monomer, there may be used, for example, aniline, pyrrole, thiophene, furan, thiophenevinylene, pyridine and derivatives of these monomers. These raw material monomers may be used alone or in combination of two or more of these raw material monomers.

The raw material monomer is preferably aniline, whereby it is possible to easily form the conductive polymer layer selectively on the surface of the carbon layer. In this case, a polyaniline-containing layer is formed as the conductive polymer layer.

Step (2) is performed, for example, by immersing the first intermediate body and a counter electrode in an electrolytic solution containing an anion (dopant), and then applying current between the first intermediate body and the counter electrode, with the first intermediate body serving as an anode , In this step, a layer of conductive polymer doped with the anion is selectively formed on the surface of the carbon layer of the first intermediate body.

As the electrolytic solution, a publicly known material can be used, and for example, a solution prepared by dissolving an anion (dopant) -containing supporting electrolyte in a solvent can be used. As the solvent, water may be used, or a non-aqueous solvent may be used in consideration of the solubility of a monomer. As the non-aqueous solvent, alcohols such as ethyl alcohol, methyl alcohol, isopropyl alcohol, ethylene glycol and polyphenylene glycol may be preferably used. As the supporting electrolyte, a conjugated acid of an anion and an alkali metal salt containing an anion (sodium salt, potassium salt, etc.) can be used.

Examples of the anion include a sulfate ion, a nitrate ion, a phosphate ion, a borate ion, a benzenesulfonate ion, a naphthalene sulfonate ion, a toluenesulfonate ion, a methanesulfonate ion (CF ₃ SO ₃ ^- ), a perchlorate ion (ClO ₄ ^- ), a tetrafluoroborate ion (BF ₄ ^- ), a hexafluorophosphate (PF ₆ ^- ), a fluorosulfate (FSO ₃ ^- ), a bis (fluorosulfonyl) imide ion (N (FSO ₂ ) 2 ^- ) and a bis (trifluoromethanesulfonyl) imide ion (N (CF ₃ SO ₂ ) 2 ^- ). These anions may be used alone or in combination of two or more of these anions.

The anion can be a polymer ion. Examples of the polymer ion include polyvinylsulfonic acid, polystyrenesulfonic acid, polyallylsulfonic acid, polyacrylic sulfonic acid, polymethacrylic sulfonic acid, poly (2-acrylamido-2-methylpropanesulfonic acid), polyisoprene sulfonic acid and polyacrylic acid. These polymers may be a homopolymer or a copolymer of two or more monomers. These polymer ions may be used alone or in combination of two or more of these polymer ions.

The electrolytic solution used in step (2) is preferably controlled to have a pH in the range of 0 to 4 and a temperature in the range of 0 ° C to 45 ° C. The current density during the electropolymerization is preferably in the range of 1 mA / cm ² to 100 mA / cm ² inclusive, whereby the conductive polymer layer can be formed safely and in a short time selectively on the surface of the carbon layer. The electrolytic solution preferably dissolves the raw material monomer at a rate of 0.1 mol / L to 3 mol / L inclusive. The electrolyte solution preferably has one Anion concentration in a range of 0.1 mol / l up to 5 mol / l inclusive.

The thickness of the conductive polymer layer can be easily controlled by suitably changing the current density during electrolysis or a polymerization time. The conductive polymer layer has a thickness in the range, for example, 50 microns to 300 microns inclusive.

The conductive polymer formed by the electropolymerization is preferably a π-conjugated polymer, and a π-electron-conjugated polymer has excellent conductivity by doping with an anion (dopant). Examples of the π-conjugated polymer that can be used include polypyrrole, polythiophene, polyfuran, polyaniline, polythiophene, vinylene, polypyridine and derivatives of these polymers. These π-conjugated polymers can be used alone or in combination of two or more of these π-conjugated polymers. The weight-average molecular weight of the conductive polymer is not particularly limited, for example, in a range of 1,000 to 100,000 inclusive.

The derivatives of polypyrrole, polythiophene, polyfuran, polyaniline, polythiophenevinylene and polypyridine relate to polymers each having as its basic structure polypyrrole, polythiophene, polyfuran, polyaniline, polythiophene and polypyridine. For example, a polythiophene derivative includes poly (3,4-ethylenedioxythiophene) (PEDOT) and the like.

FIRST EXAMPLE EMBODIMENT

In a first exemplary embodiment of the present invention, first the first intermediate body 30 who in 1 shown (step 1a). The first intermediate body 30 is a band-shaped (elongated) positive pantograph 31 educated. The first intermediate body 30 has an area (first area) on both the front surface and the rear surface 31a ) with a carbon layer formed thereon 32 and an area (second area 31b ) without a carbon layer formed thereon and a positive current collector exposed thereon 31 on. The second area 31b is in the direction of the width (along the direction W in 1 ) along the positive current collector 31 educated. The first area 31a is divided into two areas by the second area 31b in a predetermined area in the longitudinal direction along the center (along the direction L in FIG 1 ) of the positive current collector is formed.

Subsequently, the first intermediate body 30 in an electrolytic solution containing a raw material monomer, and the raw material monomer is electrolytically polymerized (step 2a). This way, as in 2 shown, the second intermediate body 40 containing a conductive polymer layer 33 which selectively on a surface of the carbon layer 32 is formed. In step (2a) no conductive polymer layer is formed 33 on the second area 31b that does not match the carbon layer 32 is covered, and even if this forms, it is only weakly formed. Therefore, it is not necessary to scrape a portion of the carbon layer and the conductive polymer layer from the surface of the positive current collector, for example using a brush.

Further, according to the present exemplary embodiment, a conduction member is in the second region 31b of the second intermediate body 40 attached, as in 3 shown (step (3a)). In 3 the hatched area indicates the area (first area 31a ) with the carbon layer 32 and the conductive polymer layer 33 which are formed in this order. The line element is for example made of a conductor wire 14A and a flat connector 15A educated. The flat plug 15A is, for example, with a surface of the second area 31b welded to the positive electrode 21 having the conduit element to form.

Alternatively, the tab can 15A through the subsequent process at the area 31b be attached. First, at least one projection on a surface of the tab 15A and then a hole in the second area 31b formed for performing the projection. Eventually, the projection becomes from an area of the second area 31b passed through the hole, and then compressed a tip of the projection to lock the tip with the other surface of the second region. For example, the tab will 15A and the second area 31b the row is provided with a bore to penetrate the tab and the second area, and one on the tab 15A burr formed in the bore can be used as a protrusion. The ridge passes through a hole in the second area 31b is formed by the drilling, and thus the tip of the ridge on the surface of the second region 31b compressed and squeezed.

In the present exemplary embodiment, the first region and the second region are provided on both surfaces of the positive current collector. However, the first region and the second region may be provided only on a surface of the positive current collector or at different positions on the front and back surfaces. That is, a position and a size of the second area may be determined according to a Size or shape of the energy storage device can be determined appropriately.

SECOND EXEMPLARY EMBODIMENT

In a second exemplary embodiment of the present invention, the first intermediate body 50 who in 4 is shown prepared (step 1b). In 4 the hatched area indicates an area (first area 41a ) with a carbon layer formed thereon 42 , The first intermediate body 50 differs from the first intermediate body 40 the first exemplary embodiment in that it is in addition to the second area 41b second areas 41c that does not have a carbon layer 42 have at both ends in the width direction (in direction W in 4 ) having. The second area 41c extends longitudinally along (along the direction L in FIG 4 ) of the band-shaped positive current collector 41 , Further, according to the present exemplary embodiment, a unit area 47 having the same construction as a structure of the first intermediate body 40 repeatedly formed along the direction L. That is, the positive pantograph 41 has an elongated plate shape extending along the direction L. One direction L1 in 4 represents a dimension along the direction L of the unit area 47. A length W1 in FIG 4 represents a dimension along the direction W of the first area 41a on which the carbon layer 42 is trained. The unit area 47 corresponds to a positive electrode for the size of an energy storage device.

The same electropolymerization step (step 2b) may be performed on the first intermediate body as in the first exemplary embodiment 50 be performed to selectively a conductive polymer layer on a surface of the carbon layer 42 to form, so as to obtain the second intermediate body.

According to the present exemplary embodiment, the positive current collector 41 , which has an elongated plate shape, are conveyed by means of a roller to continuously the first intermediate body 50 and to produce the second intermediate body. Herein can the formation of the second area 41c along the direction L result in a region which does not have a conductive polymer layer along the direction L. When the first intermediate body 50 or the second intermediate body is conveyed by a roller, the carbon layer or the conductive polymer layer can be prevented from contacting the roller by the second region 41c brought into contact with the roller. As a result, a positive electrode having excellent reliability can be manufactured efficiently and continuously.

The present exemplary embodiment further includes a step (step (3b)) of cutting out a positive electrode per unit area 47 from the second intermediate body. In particular, the second intermediate body is along the cutting line X1 cut that in 4 as a dot-dash line X1 is shown. A pair of cutting lines X1 forms both ends of the unit area 47. This makes it possible to easily form a plurality of positive electrodes from the second intermediate body. In this case, the second area 41c be cut away to form a positive electrode with the width W1.

In the same way, according to the first exemplary embodiment, a piping member may be formed along the direction W of the positive current collector 41 at the second area 41b on which neither the carbon layer 42 still the conductive polymer layer is formed, are attached. The attachment of the conduit member may be performed before or after the cutting out of the positive electrodes.

According to the exemplary embodiment, the carbon layer 42 and the conductive polymer layer in an area near the dot-dash line X1 , in the 4 shown is formed. In the second intermediate body, however, the second area may be further provided in an area between the adjacent unit areas 47 (the area near the dot-dash line X1 in 4 shown). In this case, the second intermediate body in the second area that neither the carbon layer 42 still has the conductive polymer layer, are cut so that it is unlikely that the carbon layer 42 and the conductive polymer layer is damaged by the cutting of the second intermediate body. Thus, it is possible to manufacture a positive electrode with excellent reliability efficiently and continuously.

According to the present exemplary embodiment, the conduit member has been attached. However, should it not be necessary to provide the conduit member, the first area may be in place of the second area 41b be formed without the second area 41b provided.

MODIFICATION OF SECOND EXEMPLARY EMBODIMENT

Instead of the first intermediate body 50 According to the present exemplary embodiment, the first intermediate body 60 who in 5 is shown to be formed, the three unit areas 57 that is along the direction W of the positive current collector 51 are repeatedly formed. One unit area 57 in the first intermediate body 60 corresponds to a first intermediate body 50 , In 5 the hatched area is an area (first area 51a ) on which the carbon layer 52 is trained. The first intermediate body 60 has a second area 51c between the adjacent unit areas 57 along the direction L up. A second intermediate body obtained by performing an electropolymerization step on the first intermediate body 60 is formed, along the cutting line X2 as a dash-dotted line X2 in 5 is shown, cut, and further along the cutting line Y2 as a dash-dotted line Y2 in 5 is cut to be divided into the unit areas 47 and 57. Thus, it is possible to obtain the same structure as that for the second intermediate body of the present exemplary embodiment.

According to the present modification, the second area became 51c between the adjacent unit areas 57 formed along the direction L. However, it is not necessary to use the second area between the adjacent unit areas 57 to build.

According to the present modification, the first intermediate body became 60 produced. The first intermediate body 60 includes the three unit areas 57 repeated along the direction W of the positive current collector 51 are formed. The number of repeatedly formed unit areas 57 however, is not limited to three.

[Method of manufacturing an energy storage device]

A method of manufacturing an energy storage device according to the present invention comprises the steps of: preparing a positive electrode by the method of producing a positive electrode for an energy storage device (step (A)); and stacking or winding the positive electrode, a negative electrode and a separator, with the separator being interposed between the positive electrode and the negative electrode (step (B)). The step (B) forms a stacked or wound electrode group.

The step (A) comprises the above-described steps (1) and (2).

The step (A) preferably further comprises a step of attaching a conduction member to a surface of the second region of the positive current collector in the second intermediate body, which is produced by the step (2). Since the surface of the second region in the second intermediate body produced by the step (2) is not exposed by the above-described scraping step, a clean, smooth and flat surface of the second region is maintained. Thus, the piping member can be fastened sufficiently firmly to and adhere to a predetermined area of the second area. Thus, it is unlikely that the conduction element will fall off the positive electrode due to shocks generated during transport of an energy storage device, for example, so that the energy storage device will not work. Also, contact resistance between the lead member and the positive electrode is unlikely to occur due to misconnection between the lead member and the positive electrode, so that the internal resistance of an energy storage device increases.

The negative electrode used in step (B) includes, for example, a negative current collector and a negative electrode material layer.

As the negative current collector, for example, a conductive foil material is used. Examples of the sheet material include a metal foil, a porous metal body, a punched metal, and an etched metal. As a material for the negative current collector, for example, copper, a copper alloy, nickel and stainless steel can be used.

The negative electrode material layer preferably contains as a negative electrode active material a material that electrochemically stores and releases lithium ions. Examples of such material include a carbon material, a metal compound, an alloy, and a ceramic material. As the carbon material, graphite, non-graphitizable carbon (hard carbon) and easily graphitizable carbon (soft carbon) are preferably used, with graphite and hard carbon being particularly preferred. Examples of the metal compound include silica and tin oxide. Examples of the alloy include a silicon alloy and a tin alloy. Examples of the ceramic material include lithium titanate and lithium manganate. These materials may be used alone or in combination with two or more of these materials. Of these materials, a carbon material is preferable because it is capable of achieving a low potential of the negative electrode.

For example, the negative electrode material layer preferably includes a conductive agent and a binder besides the negative electrode active material. Examples of the conductive agent include carbon black and carbon fiber. Examples of the binder include fluororesin, acrylic resin, a rubber material and a cellulose derivative. Examples of the fluororesin include polyvinylidene fluoride, polytetrafluoroethylene and a tetrafluoroethylene-hexafluoropropylene polymer. Examples of the acrylic resin include polyacrylic acid and an acrylic acid-methacrylic acid copolymer. Examples of the rubber material include a styrene-butadiene rubber, and examples of the cellulose derivative include carboxymethyl cellulose.

The negative electrode material layer is prepared by, for example, preparing a negative electrode compound paste containing a negative electrode active material mixture, a conductive agent, a binder, and the like with a dispersion medium, and applying the negative electrode compound paste on the negative current collector, and formed by subsequent drying. For the dispersion medium, for example, water or N-methyl-2-pyrrolidone (NMP) is preferably used. Subsequently, a coating film is desirably pressed between rollers to increase the strength of the negative electrode material layer.

The negative electrode is preferably predoped with lithium ions in advance. This lowers the potential of the negative electrode to increase a potential difference between the positive electrode and the negative electrode (that is, the voltage), and thus to improve the energy density of the energy storage device.

Pre-doping of the negative electrode with lithium ions is promoted, for example, by forming a metallic lithium film serving as a source of lithium ions on one surface of the negative electrode material layer and the negative electrode with the lithium metal film with a non-aqueous electrolyte solution Lithium ion conductivity is impregnated. At this time, the lithium ions are eluted from the lithium metal film into the nonaqueous electrolytic solution, and the eluted lithium ions are stored in the negative electrode active material. For example, when graphite or hard carbon is used as the negative electrode active material, the lithium ions are interposed between layers of graphite or in the fine pores of the hard carbon. A quantity of lithium ion to be predoped may be controlled by a lithium metal film mass.

A method of forming the metal lithium film on the surface of the negative electrode material layer may include a method of bonding the lithium metal foil to the negative electrode material layer or a method of depositing a lithium film on the surface of the negative electrode material layer by a vapor phase method. For example, the vapor phase method is a method using a vacuum deposition apparatus, and a metallic lithium thin film can be obtained by evaporating metallic lithium in a device in which a high degree of vacuum is maintained and depositing metallic lithium on the surface of the material layer for the negative Electrode are formed.

A step of pre-doping the negative electrode with lithium ions may be performed before assembly of the electrode group, or pre-doping may be performed after the electrode group is housed together with the non-aqueous electrolyte solution in a housing of an energy storage device. In the latter case, the electrode group can be produced after the metallic lithium film is formed in advance on the surface of the negative electrode.

As the separator in step (B), a pulp of cellulose fibers, a fiber of glass fiber, a microporous membrane of polyolefin, a fabric and a nonwoven fabric are preferably used. The separator has a thickness in the range of, for example, 10 μm to 300 μm inclusive, preferably 10 μm to 40 μm inclusive.

The method of manufacturing an energy storage device according to the present invention preferably further comprises a step of soaking the electrode group with a non-aqueous electrolyte solution.

The non-aqueous electrolyte solution has a lithium ion conductivity and contains a lithium salt and a nonaqueous solvent that dissolves the lithium salt. At this time, an anion-containing salt is used as the lithium salt, whereby it is possible to reversibly repeat doping in and dedoping from the positive electrode. On the other hand, the lithium ions obtained from the lithium salt are stored in the negative electrode.

Examples of the lithium salt include LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAlCl ₄ , LiSbF ₆ , LiSCN, LiCF ₃ SO ₃ , LiFSO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiB ₁₀ Cl ₁₀ , LiCl, LiBr, Lil, LiBCl ₄ , LiN (FSO ₂ ) ₂ and LiN (CF ₃ SO ₂ ) ₂ . These lithium salts may be used alone or in combination of two or more of these lithium salts. Of these lithium salts, at least one selected from the group consisting of a lithium salt having a halogen atom-containing oxo acid anion suitable for a second anion and a lithium salt having an imide anion is preferably used. The concentration of Lithium salt in the non-aqueous electrolyte solution may be in a range of, for example, 0.2 mol / L to 4 mol / L inclusive, and is not particularly limited.

Examples of the non-aqueous solution which can be used include cyclic carbonates such as ethylene carbonate, propylene carbonate and butylene carbonate; Chain carbonates, such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; aliphatic carboxylate esters such as methyl formate, methyl acetate, methyl propionate and ethyl propionate; Lactones such as γ-butyrolactone and γ-valerolactone; Chain ethers such as 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE) and ethoxymethoxyethane (EME); cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran; Dimethylsulfoxide, 1,3-dioxolane, formamide, acetamide, dimethylformamide, dioxolane, acetonitrile, propionitrile, nitromethane, ethylmonoglyme, trimethoxymethane, sulfolane, methylsulfolane, and 1,3-propanesulfone. These nonaqueous solvents may be used alone or in combination of two or more of these nonaqueous solutions.

The nonaqueous electrolyte solution can be prepared by adding an additive to the nonaqueous solvent as needed. For example, an unsaturated carbonate such as vinylene carbonate, vinyl ethylene carbonate or divinylethylene carbonate may be added as an additive for forming a high lithium ion conductivity coating on the surface of the negative electrode.

Hereinafter, an example of the method of manufacturing an energy storage device according to the present invention will be described with reference to FIGS 6 and 7 described. However, the method of manufacturing an energy storage device according to the present invention is not limited to this example.

First, as in 2 shown, the second intermediate body 40 get the first area 31a , on which selectively on a surface of the carbon layer 32 the conductive polymer layer 33 is formed, and a second area 31b on which a surface of the positive current collector 31 is exposed (steps (1a) and (2a)). Subsequently, as in 3 shown, the tab 15A of the conduit element with the second area 31b of the second intermediate body 40 connected (step (3a)). In this way, the positive electrode 21 made with the line element mounted thereon.

Next will be the positive electrode 21 connected to the conduit element (conductor wire 14A and tabs 15A ), the negative electrode 22 , which, with a conducting element (conductor wire 14B and tabs 15B ), and the separator 23 with the separator disposed between the positive electrode and the negative electrode, as shown in FIG 7 shown the electrode group 10 in which the conductive members are exposed from an end surface 40b of the electrode group (step (B)). The outer circumference of the electrode group 10 is with a fastening strap 24 fixed.

As in 6 shown is the electrode group 10 together with a non-aqueous electrolyte solution (not shown) in a bottomed cylindrical container 11 having an opening housed. The wires 14A . 14B are from the seal body 12 led out. The seal body 12 is in the opening of the container 11 arranged to the container 11 seal. More precisely, the container is 11 is formed at a part near an opening end so as to be bent inwardly by pulling and formed curled at the opening end, around the seal body 12 to press. The seal body 12 is formed of, for example, an elastic material containing a rubber component.

In the exemplary embodiment, a wound cylindrical energy storage device has been described. However, an application range of the present invention is not limited to the above-described example, and the present invention can also be applied to a square or stacked energy storage device.

INDUSTRIAL APPLICABILITY

An energy storage device manufactured by a method of manufacturing an energy storage device according to the present invention can be suitably used for an application in which the required capacity is higher than the capacity of an electric double layer capacitor or a lithium ion capacitor and the required output is higher than is the output of a lithium-ion secondary battery.

LIST OF REFERENCE NUMBERS

10:

electrode group

11:

container

12:

seal body

14A, 14B:

lead wire

15A, 15B:

tabs

21:

positive electrode

22:

negative electrode

23:

separator

24:

fixing tape

30, 50, 60:

first intermediate body

31, 41, 51:

positive pantograph

31a, 41a, 51a:

first area

31b, 41b, 51b:

second area

41c, 51c:

second area

32, 42, 52:

Carbon layer

33:

conductive polymer layer

40:

second intermediate body

X1, X2, Y2:

intersection

7, 57:

unit area

Claims (4)

A method of manufacturing a positive electrode for an energy storage device, the method comprising the steps of: Providing a current collector comprising a first region and a second region on a surface of the current collector, the first region having a carbon layer formed on the surface, the surface of the second region being exposed; and selectively forming a conductive polymer layer on a surface of the carbon layer by immersing the current collector in an electrolytic solution containing a raw material monomer, and then performing an electrolytic polymerization of the raw material monomer. A method for producing a positive electrode for an energy storage device according to Claim 1 further comprising a step of attaching a guide member to the second region. A method for producing a positive electrode for an energy storage device according to Claim 1 or 2 wherein: the current collector is an elongated foil, and the elongate foil comprises at least a portion of the second region longitudinally along the elongate foil. A method of manufacturing an energy storage device, the method comprising the steps of: preparing a positive electrode by the method of any one of Claims 1 to 3 ; and stacking or winding the positive electrode, a negative electrode, and a separator, wherein the separator is disposed between the positive electrode and the negative electrode.

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